1. Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
2. Department of Geology and Soil Science – UGCT, Ghent University, Krijgslaan 281 S8, 9000 Gent, Belgium
3. DICAM, Alma Mater Studiorum, University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy